How to access/edit information about included audio files?
You can edit the file path of the Sound Datablock (and any external file) using the Outliner:




From the header, make sure the outliner is set to display 'Datablocks'.
Browser to the Sounds section and find the sound datablock you want to edit.
Expand the RNA and modify the File Path string as required.
You might have to restart Blender to force a reload.